Skip to content
Trust My Mechanic
Trust My Mechanic

Your Free Car Repair Advice and Auto Repair Help

  • Home
  • About Me
  • Contact Me
  • A/C and Heater
  • Auto Repair Questions
  • Battery – Alternator
  • Brakes
  • Check Engine Lights
  • Coolant Leak
  • Exterior Care
  • Front End
  • Head Gasket Repair
  • Auto Insurance
  • Auto Loans
Trust My Mechanic

Your Free Car Repair Advice and Auto Repair Help

K&W Engine Block Sealer for Head Gasket Leaks

Austin Davis, March 7, 2013October 2, 2014

Austin

I have a blown head gasket or cracked block.  The coolant test came back positive for combustion.  I’ve tried Bar’s Leak Block Sealer and K-Seal.  Neither worked.  The coolant is bubbling out of the expansion tank so I’d say the sealer isn’t even making it to the crack as the compression is pushing it back out the tank.

Before this I did have a water pump gasket blow and I used the K&W sealer and it did fix it.  I didn’t do the 500 mile thing as I did not read about it yet.  My question is will the K&W 500 mile trick work if it’s getting blown out of the expansion tank.  K-Seal Rep told me to put it in a top radiator hose so it goes directly into the block but that did now work either.

I really don’t want to pull the heads on this if I can get some sealer to work.

Sincerely

Dan

Hello Dan

Yes in my experience KW block sealer is the only thing I have seen very impressive permanent results but use as I direct not as per can.

Keep me posted

Blessings
Austin Davis

Reader Follow Up
If I put it in the expansion tank it will just blow back out like the others.  Where should I put it in at?  Putting the K Seal in the top radiator hose by the thermostat did no good.

Dan

 

Hello again Dan

Are you absolutely sure the radiator is not restricted ….sure sounds like it. If there is that much back pressure from exhaust gases I would expect the cylinders to be full of water as well. A radiator that is stopped up at the bottom will not allow coolant to circulate.

Remove the upper radiator hose from the engine and pour the contents into the radiator. Butttttt check it out first

Blessings
Austin Davis

Reader Follow Up

Austin

I just ordered a new radiator on ebay as that is problem my main problem and what caused the head gasket failure.  I remember I had to change the back heater hose assemble due to some of them being rusted out.  That rust probably clogged up the radiator which then caused the overheating and head gasket and water pump gasket failures.

Thanks for all your help.  You’re a very good man for doing what you do.

Dan

No problem Dan
Thanks! Fingers crossed, keep me posted. I would replace the radiator and thermostat first and see what happens before using the sealer or anything else

Blessings
Austin Davis

MY INSTRUCTIONS FOR USING K&W BLOCK SEALER

1. Drain the cooling system of all (as much as you possibly can) of antifreeze

2. Mix a can of K&W Engine Block Sealer or Nano Tech Version in a bucket with tap water and mix thoroughly.

3. Fill up the radiator slowly with that bucket mix and top off system with tap water.

4. Drive the vehicle for a total of 500 miles, then drain out sealer and refill system with coolant and water mix (usually 50/50)

I do not mess with removing the thermostat or pulling the spark plugs etc. as it says to do on the can. We have been doing it this way for MANY years with great success.

****You will not have any freeze or boil over protection, so during the 500 mile period keep your engine and radiator from freezing weather. Ok!

Related Posts:

  • How to Replace the Thermostat in Your Car
  • What Your Exhaust Smoke Is Trying To Tell You?
  • Why Does My Car Overheat?Understanding the Common…
  • Why is my diesel blowing white smoke
  • How to Fix White Smoke from a Diesel Engine: Common…
Over Heating engine overheatingheadgasket leakK&W block sealer

Post navigation

Previous post
Next post
  • (no title)
  • Front and rear Brake Pads and Rotors
  • How do disc brakes work in cars and light vehicles
  • How do hydraulic brakes in cars and light vehicles work 3D animation
  • Look at How Far my Project Car has Come in a Year
  • 7 Things You Shouldn’t Do In an Automatic Transmission Car
  • How to Change EVERY FLUID in your Car or Truck 
  • 10 Winter Car TIPS & TRICKS you NEED to Know
  • How Much Weight can you REMOVE from your Car?
  • What Happened to the LEMONS BMW?
  • What it Actually Takes to Race a $500 Car for 24 Hours!
  • How to Install Windshield Wiper Brakes
  • How to Replace a Hybrid Battery in a Prius
  • How To Install A Flex Fuel e85 Conversion Kit In Your Car
  • How To Fix A Leaking Rear Axle 
  • How to Install Windshield Wiper Brakes
  • How to Perfectly Maintain Your First Car
  • How To Make Your Car Last A Long Time – Simple Checks
  • 12 Things To Check Before Buying A Used Car
  • Priced for Perfection: The World’s Most Expensive Cars
  • How To Drive A Manual Transmission + Rev Match + Heel Toe Downshift
  • How to Buy a Car To Flip for a Profit 
  • How to Buy a Used Car Interior and Exterior Inspection
  • How to Inspect a Used Car for Purchase

©2025 Trust My Mechanic | WordPress Theme by SuperbThemes